Nuclear Medicine? It's Probably Not At All What You Think It Is

January 2, 2019

Jean-Luc Urbain, M.D., Ph.D., has worked in nuclear medicine for more than 30 years in three countries. He is a recognized leader in the field – he was recently elected president-elect of the World Federation of Nuclear Medicine and Biology – and an avid proponent of the discipline’s numerous capabilities.

He also knows his chosen field has a serious image problem.

“Nuclear medicine is largely unknown, even among medical professionals,” said Urbain, who joined Wake Forest Baptist Medical Center as head of the section on nuclear medicine in May 2018.

“And when most people hear ‘nuclear’ or ‘radiation’ they think of Hiroshima and Nagasaki, Three Mile Island, Chernobyl, Fukushima, all negative associations. That’s unfortunate.”

So if nuclear medicine doesn’t have anything to do with atomic bombs or reactor meltdowns, what is it?

The radioactive materials – generally called radiopharmaceuticals or medical isotopes – consist of a radioactive atom bonded to targeting molecules that are formulated to go to a specific part of the body. These compounds are usually administered to patients by intravenous injection in doses determined by the individual’s body weight, the reason for the scan and the part of the being examined.

In the body the radiopharmaceuticals emit energy in the form of rays that are detected by special devices which work with computers to produce precise images of the targeted areas.
Those images differ from those produced by other technologies. X-rays, CT scans and ultrasound send forms of energy into the body from outside and produce images of physical structures. Nuclear medicine’s PET and SPECT scans, on the other hand, use the radiation coming from inside the body to depict activity in tissues and organs at the molecular and cellular levels.

“Other scans show you anatomy, what a part of the body look like,” Urbain said. “Nuclear medicine shows how it’s functioning.”

This allows physicians to determine the presence, location, extent and severity of a wide range of diseases – including cancer, heart disease and brain disorders – often at very early stages, before they can be detected by other methods.

Nuclear imaging also can help doctors select treatments, evaluate their effectiveness, measure changes in cellular activity and track the progression or remission of disease.

Nuclear medicine is not, however, a first option for diagnosis. Physicians order and review the results of conventional testing or imaging – which provide sufficient information about a disease or condition in the majority of cases – before referring patients to nuclear medicine specialists.

“Nuclear medicine is safe, and a noninvasive imaging tool that provides precise information you don’t get from other methods,” Urbain said.

And it has gotten better in recent years through the development of hybrid imaging, in which nuclear PET or SPECT scans are done simultaneously with CT scans. This practice produces composite images that contain well-defined functional and anatomical information from both technologies.

Still, the radioactive aspect of nuclear medicine can be a little intimidating – if not outright scary – for some people. But there’s little reason for that.

Nuclear medicine procedures have been performed on people without adverse effect since the 1950s. The amount of radiation exposure in nuclear imaging is comparable to that from X-rays and CT scans. And nuclear medicine specialists follow the ALARA principle.

“That stands for ‘As Low As Reasonably Achievable,’” said Jonathan Richardson, the chief nuclear medicine technologist at Wake Forest Baptist. “This means using the amount of radioactive material that will produce a useful image with the least amount of radiation exposure for the patient.”

Similarly, the amount of time that the radioactive material remains radioactive is kept to a minimum.

“It depends on what you’re looking at and what you’re looking for,” Urbain said. “For some scans, the radioactivity can last for just 10 minutes. For others, it might be three days. But it’s always the shortest time possible.”

While nuclear medicine is most frequently used for diagnosis it is effective as a treatment, notably for certain forms of cancer. The amounts of radioactivity and the times of exposure are greater for therapy than diagnosis, but the level of risk to patients remains low.

Treatment is widely regarded as the area of nuclear medicine with the greatest potential for growth, especially the practice of theranostics, which is the use of a single targeting compound in both therapy and diagnostics.

“It’s a great type of precision medicine,” Urbain said. “First we locate the problem cells, then we go back to that exact location with internal radioactive probes to kill them.”

Under Urbain’s direction, Wake Forest Baptist established a theranostics clinic in September 2018. Using radiopharmaceuticals approved by the FDA earlier this year, the clinic is devoted to the treatment of neuroendocrine tumors, an extremely rare form of cancer related to hormone production. To date, six patients have begun the clinic’s eight-month therapy regimen, and there are 14 on a waiting list.

Urbain said that as more new radiopharmaceuticals are developed and gain Food and Drug Administration approval the use of theranostics will expand to include the diagnosis and treatment of breast cancer, prostate cancer and other more common forms of the disease.
“It’s a comprehensive, personalized medicine approach that works,” he said.

Disclaimer: The information on this website is for general informational purposes only and SHOULD NOT be relied upon as a substitute for sound professional medical advice, evaluation or care from your physician or other qualified health care provider.